P 50 Orthoceras gregarioides.
| 分類 | Animals: Mollusca: Mollusca Proper: Cephalopoda: |
| 年代 | Paleozoic Silurian Lower Silurian: |
| 産地 | Calvados. |
| 文献 | Department of Science, Tokio-Daigaku, 1881: Cambrian and Silurian formation. Catalogue of Histrical Geology. Palaeozoic., pp. 1–15. Department of Science, Tokio-Daigaku. |
